摘要 :
The active appearance models (AAMs) provide the detailed descriptive parameters that are useful for various autonomous face analysis problems. However, they are not suitable for robust face tracking across large pose variation for...
展开
The active appearance models (AAMs) provide the detailed descriptive parameters that are useful for various autonomous face analysis problems. However, they are not suitable for robust face tracking across large pose variation for the following reasons. First, they are suitable for tracking the local movements of facial features within a limited pose variation. Second, they use gradient-based optimization techniques for model fitting and the fitting performance is thus very sensitive to initial model parameters. Third, when their fitting is failed, it is difficult to obtain appropriate model parameters to re-initialize them. To alleviate these problems, we propose to combine the active appearance models and the cylinder head models (CHMs), where the global head motion parameters obtained from the CHMs are used as the cues of the AAM parameters for a good fitting or re-initialization. The good AAM parameters for robust face tracking are computed in the following manner. First, we estimate the global motion parameters by the CHM fitting algorithm. Second, we project the previously fitted 2D shape points onto the 3D cylinder surface inversely. Third, we transform the inversely projected shape points by the estimated global motion parameters. Fourth, we project the transformed 3D points onto the input image and computed the AAM parameters from them. Finally, we treat the computed AAM parameters as the initial parameters for the fitting. Experimental results showed that face tracking combining AAMs and CHMs is more pose robust than that of AAMs in terms of 170% higher tracking rate and the 115% wider pose coverage.
收起
摘要 :
The active appearance models (AAMs) provide the detailed descriptive parameters that are useful for various autonomous face analysis problems. However, they are not suitable for robust face tracking across large pose variation for...
展开
The active appearance models (AAMs) provide the detailed descriptive parameters that are useful for various autonomous face analysis problems. However, they are not suitable for robust face tracking across large pose variation for the following reasons. First, they are suitable for tracking the local movements of facial features within a limited pose variation. Second, they use gradient-based optimization techniques for model fitting and the fitting performance is thus very sensitive to initial model parameters. Third, when their fitting is failed, it is difficult to obtain appropriate model parameters to re-initialize them. To alleviate these problems, we propose to combine the active appearance models and the cylinder head models (CHMs), where the global head motion parameters obtained from the CHMs are used as the cues of the AAM parameters for a good fitting or re-initialization. The good AAM parameters for robust face tracking are computed in the following manner. First, we estimate the global motion parameters by the CHM fitting algorithm. Second, we project the previously fitted 2D shape points onto the 3D cylinder surface inversely. Third, we transform the inversely projected shape points by the estimated global motion parameters. Fourth, we project the transformed 3D points onto the input image and computed the AAM parameters from them. Finally, we treat the computed AAM parameters as the initial parameters for the fitting. Experimental results showed that face tracking combining AAMs and CHMs is more pose robust than that of AAMs in terms of 170% higher tracking rate and the 115% wider pose coverage.
收起
摘要 :
Six new analogs of 2-methylene-19-nor-1α,25-dihydroxyvitamin D 3, 6-7 and 8a,b-9a,b, have been synthesized. All compounds are characterized by a trans double bond located in the side chain between C-22 and C-23. While compounds 6...
展开
Six new analogs of 2-methylene-19-nor-1α,25-dihydroxyvitamin D 3, 6-7 and 8a,b-9a,b, have been synthesized. All compounds are characterized by a trans double bond located in the side chain between C-22 and C-23. While compounds 6 and 7 possess C-26 and C-27 methyls, compounds 8a,b and 9a,b lack one of these groups. A Lythgoe-based synthesis, employing the Wittig-Horner reaction was used for these preparations. Two different types of Δ22E-25-hydroxy Grundmann's ketone, having either only one stereogenic center located at position C-20 (20 and 21), or two stereogenic centers located at 20- and 25-positions (24a,b-25a,b) were obtained by a multi-step procedure from commercial vitamin D2. The introduction of a double bond at C-22 appeared to lower biological activity in vitro and in vivo. Further removal of a 26-methyl in these analogs had little effect on receptor binding, HL-60 differentiation and CYP24A expression but markedly diminished or eliminated in vivo activity on bone calcium mobilization while retaining activity on intestinal calcium transport.
收起
摘要 :
A method is proposed for generation of the centerline of 3D tubular shapes using an extensible-skeleton model. Starting from a user-selected point, the skeleton grown by iteratively adding subsequent centerline points within a pre...
展开
A method is proposed for generation of the centerline of 3D tubular shapes using an extensible-skeleton model. Starting from a user-selected point, the skeleton grown by iteratively adding subsequent centerline points within a prediction-estimation scheme controlled by a multi-scale analysis of the image moments. The location of the next point is predicted according the local orientation of the tubular structure. The coordinates of the predicted point are corrected under the influence of image forces and of prior model shape constraints. The extraction of artery centerlines from magnetic resonance angiography (MRA) images is described. The goal is a quantitative assessment of arterial stenoses based on cross-sectional diameters and areas of the vessel contours in the planes locally perpendicular to the centerline. For this purpose, iso-contours extraction based on an adaptive local iso-value have been implemented. The robustness and accuracy of the method have been demonstrated on MRA data on 5 reference phantoms and on 17 patients' carotid arteries, 97% of the centerlines were exploitable in the carotid arteries (100% in the phantoms). On average, the centerlines were extracted within 1 second, and the whole quantification process took less than 1 minute per artery, including interaction and display. The Mean difference (± standard deviation) between stenosis percentages, semi-automatically measured and visually estimated by radiologists, was 0.23% ± 7.89%. The reproducibility of the semi-automatic method was significantly better.
收起
摘要 :
Oxadiazole derivatives are an important class of heterocyclic compounds, reported to possess a wide spectrum of biological activities. Moreover, oxadiazole nucleus occupies a very important place in the field of antioxidant agents...
展开
Oxadiazole derivatives are an important class of heterocyclic compounds, reported to possess a wide spectrum of biological activities. Moreover, oxadiazole nucleus occupies a very important place in the field of antioxidant agents. The above observations prompted us to synthesize some novel oxadiazoles derivatives with various substitutions at along with heterocyclic rings in the same framework for synergistic action. We here in report the synthesis, antioxidant screening & QSAR studies of the new title compounds. Concentrated research on 2-(ω-chloro substituted amino)-5- (p-chlorophenyl)-1,3,4-oxadiazole & were synthesized, screened for antioxidant activities & QSAR studies. All new entities have good yield & results. From antioxidant activity results, it was observed that the compounds with both electron donating and electron withdrawing groups on the aldehydic phenyl ring influenced the activity. Among all the compounds tested GS-9i-c, GS-9i-e and GS-9i-h showed the good % inhibition and were found to be more significant compound among all the compounds tested. 2D & 3D-QSAR models with moderate to high predictive ability of oxadiazole derivatives were derived. The role of hydrophobicity as a 3D property was confirmed and also Electrostatic and Steric effects were found to contribute to antioxidant activity.
收起
摘要 :
The development of cost-effective co-catalysts of high photocatalytic activity and recyclability is still a challenge in the energy transformation domain. In this study, 0D/2D Schottky heterojunctions, consisting of 0D ZnO and 2D ...
展开
The development of cost-effective co-catalysts of high photocatalytic activity and recyclability is still a challenge in the energy transformation domain. In this study, 0D/2D Schottky heterojunctions, consisting of 0D ZnO and 2D Ti3C2, were successfully synthesized by the electrostatic self-assembling of ZnO nanoparticles on Ti3C2 nanosheets. In constructing these heterojunctions, Ti3C2 nanosheets acted as a co-catalyst for enhancing the transfer of excitons and their separation to support the photocatalytic response of ZnO. The as-prepared ZnO/Ti3C2 composites demonstrate an abbreviated charge transit channel, a huge interfacial contact area and the interfacial electrons’ transport potential. The extended optical response and large reactive area of the ZnO/Ti3C2 composite promoted the formation of excitons and reactive sites on the photocatalyst’s surface. The ZnO/Ti3C2 Schottky heterojunction showed significantly high photocatalytic activity for hydrogen production from a water–ethanol solution under the light illumination in the visible region. The hydrogen evolution overoptimized the ZnO/Ti3C2 composition with 30 wt.% of Ti3C2, which was eight times higher than the pristine ZnO. These findings can be helpful in developing 0D/2D heterojunction systems for photocatalytic applications by utilizing Ti3C2 as a low-cost co-catalyst.
收起
摘要 :
Simultaneous regulation of electronic environment of active sites and engineering architectures with efficient exposed active sites are crucial to realize efficient persulfate activation for pollutants degradation, which remains a...
展开
Simultaneous regulation of electronic environment of active sites and engineering architectures with efficient exposed active sites are crucial to realize efficient persulfate activation for pollutants degradation, which remains a great challenge. This study demonstrated an ingenious platform of 0D/3D nanofibrous N-enriched carbon hybrid with incorporated ultrafine metal oxide quantum dots (QDs, & AP;3 nm) with abundant oxygen vacancies that enabled efficient PDS activation for pollutants degradation via integrating electron density regulation and morphology modulation. The favorable structure configuration and intimate coupling action between QDs and N-doped carbon matrix promoted PDS activation on the surface of Fe3O4 QDs@NC and simultaneously modified pollutant absorption property towards catalyst, synergistically resulting in excellent TC degradation efficiency. More importantly, electron-rich Fe sites derived from electron redistribution and highly-conductive N-doped carbon matrix synergistically directed PDS activation by non-radical pathway with generation of 1O2. This work provides a fresh insight into improving persulfate activation by engineering architectures and regulating local electronic density of multiple active sites.
收起
摘要 :
In this paper, we propose a method for classification 3D human activities using the complementarity of CNNs, LSTMs, and DNNs by combining them into one unified architecture called CLDNN. Our approach is based on the prediction of ...
展开
In this paper, we propose a method for classification 3D human activities using the complementarity of CNNs, LSTMs, and DNNs by combining them into one unified architecture called CLDNN. Our approach is based on the prediction of 3D Zernike Moments of some relevant joints of the human body through Kinect using the Kinect Activity Recognition Dataset. KARD includes 18 activities and each activity consists of real-world point clouds that have been carried out 3 times by 10 different subjects. We introduce the potential for the 3D Zernike Moment feature extraction approach via a 3D point cloud for human activity classification, and the ability to be trained and generalized independently from datasets using the Deep Learning methods. The experimental results obtained on datasets with the proposed system has correctly classified 96.1% of the activities. CLDNN has been shown to provide a 5% relative improvement over LSTM, the strongest of the three individual models.
收起
摘要 :
Vitamin D, its importance in different processes taking place in the human body, the effects of abnormal levels of this hormone, either too low or too high, and the need for supplementation have been extensively researched thus fa...
展开
Vitamin D, its importance in different processes taking place in the human body, the effects of abnormal levels of this hormone, either too low or too high, and the need for supplementation have been extensively researched thus far. Variances in exposure to sunlight can cause vitamin D levels to fluctuate. Indoor activity can be a factor for these fluctuations and can lead to a decrease in vitamin D levels. We conducted a systematic review and meta-analysis aiming to identify whether indoor compared to outdoor training has a significant influence on vitamin D levels;we also performed subgroup analyses and multivariate meta-regression. The type of training has an impact on vitamin D levels that is influenced by multiple cofounders. In a subgroup analysis not considering cofounders, the mean serum vitamin D was 3.73 ng/mL higher in outdoor athletes, a difference which barely fails to achieve significance (p = 0.052, a total sample size of 5150). The indoor–outdoor difference is only significant (clinically and statistically) when considering studies performed exclusively on Asian athletes (a mean difference of 9.85 ng/mL, p <0.01, and a total sample size of 303). When performing the analyses within each season, no significant differences are observed between indoor and outdoor athletes. To control for multiple cofounders (the season, latitude, and Asian/Caucasian race) simultaneously, we constructed a multivariate meta-regression model, which estimated a serum vitamin D concentration lower by 4.446 ng/mL in indoor athletes. While a multivariate model suggests that outdoor training is associated with slightly higher vitamin D concentrations when controlling for the season, latitude, and Asian/Caucasian race, the type of training has a numerically and clinically small impact. This suggests that vitamin D levels and the need for supplementation should not be decided based on training type alone.
收起
摘要 :
The experiments of electrical resistivity and thermopower on Nd0.75Sr1.25CoO4 film in the temperature range 90 KoTo310 K were carried out. The great difference in the activation energies estimated from thermopower and resistivity,...
展开
The experiments of electrical resistivity and thermopower on Nd0.75Sr1.25CoO4 film in the temperature range 90 KoTo310 K were carried out. The great difference in the activation energies estimated from thermopower and resistivity, a characteristic of small polarons, is observed, providing strong evidence for polaron-dominated transport mechanism in this material. Furthermore, the activation energy at intermediate-temperature region is larger than that at low-temperature region in resistivity, but it is not observed in thermopower, indicating that the energy for the creation of the carriers is slightly lower at low-temperature region than that at intermediate-temperature region. At the same time, the abrupt drop in the thermopower and the abnormal peak in the differential curve of resistivity indicate that a phase transition between a paramagnetic state and a ferromagnetic state occurs at temperature about 218 K. The positive thermopower in the whole temperature range measured suggests that the carriers are holes in this system.
收起
原文获取